Lion Voltron requires specialized keys to start and operate the lions. Each Lion has a specific key assigned to it which will only operate that lion. In normal form, the key is oval, with half of the seal of Arus on each side of a silver metal "block". The block is embossed with the crown and cross sigil found on the Arus seal. Normally, the key is worn on the pilot's uniform, attached by the block. There have not been keys for the Voltron lions from Legendary Defenders as of yet.
In order to use the key and activate the lion, the pilot removes the key from the block/holder, and places the key into the lock, which is shaped as an oval receptacle above the controls and viewscreen of the lion they are piloting. When inserted, the halves of the key slide together, forming the "bow" of the key, which is the seal of Arus, and reveal the gold metal "pin" and "cuts" of the key. These then rotate into position, two silver-colored metal bars lock the key into place via the cuts, and the whole key slides into the "unlock" position in the lock. Once this takes place, the activation "star" above the lock, starting at the top, lights up in succession until the center section lights. This signals that the key has been accepted and the lion is activated and ready for action.